Hiding Technical Server Information 
If you want to hide server information, you have to configure or replace all error pages of the AS Java with custom ones. You can do this for pages returned by Internet Communication Manager (ICM) and the Web Container service.
Procedure
Configuring the Web Container and ICM Error Pages
You can configure the standard error handling mechanism implemented in the ICM so it is suitable for your application. To provide less information in the error pages due to security reasons, set the value of the parameter is/HTTP/show_detailed_errors to FALSE.
More information: Error Handling
There are several ways to modify the error handling mechanism provided by the Web Container. You can customize only the look-and-feel, or the functionality of the error pages, or both.
More information: Configuring HTTP Error Handling
You can choose whether to show detailed information in the error pages generated by the Web Container, or not, by specifying the property DetailedErrorResponse in the SAP NetWeaver Administrator. By default the property is set to false, which means that all AS Java-relevant information is hidden.
More information: Troubleshooting Application Errors
Recommendation
We recommend that you override the default error pages or configure them appropriately for productive use as described above.
Specifying the UseServerHeader property
In addition, you can specify whether the server header contains the name of the server that responds to a request. To do that you have to set the value of the property UseServerHeader to true.
More information: HTTP Provider Service